The present invention relates generally to optical systems, and more particularly to a design for optical mirrors.
Optical systems, including modern lasers, commonly include mirrors among their optical components. Unfortunately, these mirrors are subject to thermal distortions and have reflectivities which are less than 100%. The task of reducing these thermal distortions and improving the reflectivities of optical mirrors is alleviated, to some extent, by the systems of the following U.S. Patents, the disclosures of which are incorporated by reference:
U.S. Pat. No. 3,609,589 issued to Hufnagel; PA1 U.S. Pat. No. 3,703,813 issued to Olevitch et al; PA1 U.S. Pat. No. 4,343,533 issued to Currin et al; PA1 U.S. Pat. No. 4,415,234 issued to Meyers; and PA1 U.S. Pat. No. 4,431,269 issued to Barnes, Jr.
Olevitch et al disclose an electrically conductive laser beam reflector that is cooled by a high voltage electrostatic field. The cooling effect of the electrostatic field has essentially the same distribution as the heating effect of the laser beam impinging on the reflector. The result is a reduction of different and varying temperature gradients in the reflector and the resulting distortions in the beam.
Barnes, Jr. is directed to a cooled laser mirror constructed with a substrate formed of a material having a thermal conductivity peak in a cryogenic temperature operating range. During operation the temperature of the substrate is maintained at cryogenic temperatures to insure peak thermal conductivity.
In Currin et al a solar radiation reflector is made using a laminate including cellulosic material and a curred polymer. In Hufnagel the coefficients of thermal expansion of bonded layers in a mirror construction are selected to balance out the tendency of the mirror to warp due to thermal gradients. Meyers uses heat-absorbing phase-change materials to provide passive cooling in a mirror.
All of the systems cited above are exemplary in the art, and indicate that there remains a need to reduce the thermal distortions in optical mirrors. The present invention is intended to help satisfy that need.